Trajectory detection and feedback system

ABSTRACT

A disclosed device provides a trajectory detection and feedback system. The system is capable of detecting one or more moving objects in free flight, analyzing a trajectory of each object and providing immediate feedback information to a human that has launched the object into flight, and/or one or more observers in the area. In a particular embodiment, a non-intrusive machine vision system that remotely detects trajectories of moving objects may be used to evaluate trajectory parameters for a basketball shot at a basketball hoop by a player. The feedback information, such as a trajectory entry angle into the basketball hoop and/or an entry velocity into the hoop for the shot, may be output to the player in an auditory format using a sound projection device. The system may be operable to be set-up and to operate in a substantially autonomous manner.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority under 35 U.S.C. §120 and is aContinuation of co-pending U.S. patent application Ser. No. 12/015,445,filed Jan. 16, 2008, which claims priority under 35 U.S.C. §119(e) toU.S. Provisional Patent Application No. 60/880,773, filed on Jan. 16,2007. U.S. patent application Ser. No. 12/015,445 further claimspriority under 35 U.S.C. §120 and is a Continuation-in-Part applicationof U.S. patent application Ser. No. 11/508,004, filed Aug. 21, 2006, nowU.S. Pat. No. 7,854,669, which is a Continuation-in-Part and claimspriority under 35 U.S.C. §120 to U.S. patent application Ser. No.10/242,373, filed Sep. 11, 2002, now U.S. Pat. No. 7,094,164. U.S.patent application Ser. No. 10/242,373 claims priority under 35 U.S.C.§119(e) from the following three U.S. Provisional Patent Applications:60/323,029, filed Sep. 12, 2001; 60/348,057, filed Jan. 11, 2002; and60/395,875 filed Jul. 12, 2002. Each of the above provisional andnon-provisional applications are incorporated herein by reference intheir entirety.

BACKGROUND OF THE INVENTION

The invention relates to apparatus and methods for sports training. Inparticular, a trajectory detection, analysis and feedback system isprovided for analyzing the trajectory of an object launched by a humanand providing feedback information regarding the trajectory to thehuman.

There are many different games of skill played by human for recreationaland competitive purposes. In many of these games of skill, such asbasketball, soccer, golf, football, baseball, softball, tennis,volleyball, racket ball, water-polo, lacrosse, bowling, shot-put,bowling and javelin, an object is thrown, kicked or struck to launch theobject along a trajectory. Often a player's success at the game iscontingent upon their skill and consistency at controlling thetrajectory of the object used in the game. For instance, a basketballplayer's success is contingent upon the ability to consistently shoot abasketball into a hoop under a variety of conditions. Thus, a basketballis launched along trajectory by the player with the objective of thetrajectory terminating within an area defined by the hoop.

Whether the game is played recreationally or professionally, playersgenerally desire to improve their skills to increase their success atthe game. There are many approaches that the player may take to improvetheir performance. These approaches include reading books, watchingvideotapes, receiving lessons/coaching, practicing and utilizingtraining devices.

Many different types of training devices have been developed fordifferent types of sports that are geared toward improving a player'sskill. One drawback of these devices is that typically they are appliedin a manner that departs from the actual play of the sport. Thedeparture from normal playing conditions can limit the effectiveness ofthe device. For instance, training devices can be used that are attachedto a player to help them develop a prescribed trajectory control skill.However, these training devices are not used in the actual play of thegame and can be a distraction to the player employing the device. Thus,the player may find any training benefits from using the device areoutweighed by the intrusiveness of the device.

As another example, the training devices can require that objects orequipment not normally used in the play of the game be used, such asspecial club that is used to improve a player's golf swing or a tee forholding a baseball that is used to improve a baseball swing. Thus, theplayer may get proficient at using the special equipment and yet notperform well when they are required to use actual equipment in actualplaying conditions. As another example, training devices have beendeveloped that must be used in an environment, such as a special room,that is significantly different from the environment where the game isplayed. Training under these simulated conditions may not translate toperformance improvement in actual playing conditions. Further, thedevices used in a special environment, are usually difficult to set-upand require another person, besides the player, to operate the device.

Another drawback of current training devices is that the player is notprovided any feedback that they can use to evaluate their performance orthe feedback can be quite detached from the training experience. When aplayer receives a lesson or coaching, another person watches theirperformance and can provide immediate feedback that is valuable to theplayer. With current training devices, the player uses the device andthen later can attempt to judge their performance based upon whetherthey perceive an improvement in their actual play of the game. However,when the player is using the device improperly or training in a lessthan optimal manner, the devices do not provide any objective feedbackthat the player can use to evaluate their performance.

In view of the above, it is desirable to provide training devices andmethods that allow the player to improve their trajectory skills forgames requiring such skills where the training devices are 1)non-intrusive, 2) operable in an environment that approximates actualplaying conditions, 3) simple to set-up and to operate and 4) provideimmediate and objective feedback to the user of the device.

SUMMARY OF THE INVENTION

This invention addresses the needs indicated above by providing atrajectory detection and feedback system. The system is capable ofdetecting one or more moving objects in free flight, analyzing atrajectory of each object and providing immediate feedback informationto a human that has launched the object into flight. The feedbackinformation may include one or more trajectory parameters that the humanmay use to evaluate their skill at sending the object along a desiredtrajectory. In a particular embodiment, a non-intrusive machine visionsystem that detects trajectories of moving objects may be used toevaluate trajectory parameters for a basketball shot at a basketballhoop by a player. The feedback information, such as a trajectory entryangle into the basketball hoop and/or an entry velocity into the hoopfor the shot, may be output to the player in an auditory format using asound projection device. The system may be operable to be set-up and tooperate in a substantially autonomous manner. After the system hasevaluated a plurality of shots by the player, the system may provide 1)a diagnosis of their shot consistency, 2) a prediction for improvementbased upon improving their shot consistency and 3) a prescription ofactions for improving their performance.

One aspect of the present invention is a device for providing trajectorydetection and feedback. The device may be generally characterized ascomprising: 1) one or more sensors for detecting physical informationused to characterize a trajectory of an object launched along itstrajectory by a human; 2) a logic device designed or configured to i)generate trajectory parameters that characterize one or more states ofthe object along it's trajectory from the physical information and ii)generate feedback information using the trajectory parameters; and 3)one or more feedback output mechanisms for providing the feedbackinformation to the human. The device may be designed to detectinformation in a non-intrusive manner such that the one or more sensorsis not located on the object, on the human or on a device attached tothe human or the sensors are not noticed by the human. For ease of use,the device may be capable to be set-up and/or to operate in anautonomous manner. The feedback information may be used by the human toimprove their skill at launching the object along a desired trajectory.

In particular embodiments, the physical information may be provided viaone of an energy signal reflected from the object or an energy signalemitted from a signal source located on the object. The device mayinclude a signal source for emitting energy signals that are detected bythe one or more sensors. The energy signals may be electromagneticenergy signals or an acoustic energy signals. For a sensor systemincluding the one or more sensor that is set-up in a particularlocation, an object that is launched into its trajectory by the human atone of a plurality of locations on a playing surface may be detected andmay be analyzed by the system. In one embodiment, the sensor system maybe able to detect trajectories for a basketball shot from a numberdifferent locations on a basketball court.

The one or more sensors may be a camera or charge coupling device. Thecamera and/or charge coupling device may be part of a machine visionsystem. Thus, the physical information may be video frame data recordedby a video camera. The camera may also be used to record physicalinformation about the human. The physical information about the humanmay be analyzed by the system to provide additional feedbackinformation.

Prior to its launch, the object may be grasped by the human and forcesused to launch the object along its trajectory may be applied via one orboth hands. Also, to launch the object along its trajectory, the objectmay be hit with a hand-held device grasped by the human. The object maybe launched by the human as part of game of skill where the objective ofthe game of skill is to launch the object along a trajectory thatterminates within a selected area. In one embodiment, the game of skillis basketball and the selected area is a basketball hoop. A playing areawhere the trajectory is generated may be the playing area where the gameof skill is normally played, such as a basketball court. The one or moresensors may be remote sensors located outside of the playing area or maybe non-intrusive sensors located within the playing area that do notaffect the play of the game of skill in the playing area.

In other embodiments, the logic device may be further designed orconfigured to generate a curve fit from the physical information thatapproximates the object's trajectory and the trajectory parameters. Inparticular, the curve fit may be a parabolic arc. The curve-fit may beused to generate trajectory parameters corresponding to different statesalong the object's trajectory such as an initial state of thetrajectory, a final state of the trajectory or any of the states of thetrajectory between the initial state and the final state. However, insome embodiments, the trajectory parameters may be generated without theuse of a curve-fit. Some examples of the trajectory parameters mayinclude but are not limited to a speed, a directional velocitycomponent, a position, a rotation rate, one or more axis's of rotation,one or more directional angles and a directional acceleration component.

After the trajectory of the object has been detected and characterized,feedback information may be generated and may be provided to the human.The feedback information may be used for performance evaluation or bythe human to improve their skill at launching the object along atrajectory that terminates within a selected area. The feedbackinformation may be one of 1) one of the trajectory parameters, 2) aplurality of the trajectory parameter and 3) a feedback parametergenerated from a combination of trajectory parameters. The feedbackinformation may be provided to the human in at least one of a visualformat, an auditory format, a kinetic format and combinations thereof.In some instances, the feedback information may be provided in analpha-numeric format which is transmitted to the player via a visualdisplay or through a sound projection device. In various embodiments,the feedback information may be qualitative or quantitative in nature.

The feedback information may be provided to the human prior to theobject reaching the end of its trajectory. For example, the object maybe a basketball and the feedback information may be one of an entryangle that the basketball enters a basketball hoop and a speed that thebasketball enters the basketball hoop. This feedback information may beprovided to the player before the basketball reaches the basketball hoopor within a short period of time after the basketball passes through thehoop.

In particular embodiments, the device may be capable of generatingtrajectory parameters and providing feedback information for each of aplurality of different trajectories in a trajectory session. The devicemay further comprise a memory storage device for storing trajectorysession information wherein the trajectory session information comprisesone or more of 1) physical information, trajectory information andfeedback information generated for the plurality of trajectories, 2) atrajectory session time, 3) a trajectory session date, 4) a trajectorysession location and combinations thereof. The device may also comprisea database for relating the trajectory session information to humanidentification information.

In a trajectory session, the plurality of trajectories that are detectedand analyzed may be generated by a plurality of different players.During the trajectory session, two or more objects may be in flight at asame time. The device may be capable of detecting, analyzing andproviding feedback information for the trajectories of two or moreobjects in flight at the same time. The two or more trajectories thatare in flight at the same time may be generated by the same player ormay be generated by two or more different players.

In a particular embodiment, the device may include session analysissoftware for one or more of 1) providing a list or a plot of trajectorysession information comprising one or more of physical information,trajectory parameters and feedback information for the plurality oftrajectories, 2) comparing the trajectory session information from thetrajectory session with trajectory session information from one or moredifferent trajectory sessions, 3) generating trajectory sessionparameters used to characterize a human's performance in the trajectorysession, 4) predicting performance improvement as a function of thetrajectory session parameters and 5) prescribing actions for improvingperformance.

Another aspect of the present invention provides a device for analyzinga trajectory of a basketball, the device comprising: 1) one or morecameras for recording video frame data used to characterize a trajectoryof a basketball shot by a human; 2) a logic device designed orconfigured to i) to receive the video frame data, ii) generatetrajectory parameters that characterize one or more states of thebasketball along it's trajectory and iii) generate feedback informationusing the trajectory parameters; and 3) one or more feedback outputmechanisms for providing the feedback information to the human. Thefeedback information may be used by the human to improve their skill atshooting the basketball. A playing area where the basketball is shot maybe one where a basketball game is normally played, such as a gymnasium,arena or outdoor basketball court. For ease of use, the device may becapable of autonomous set-up or autonomous operation.

In a particular embodiment, the one or more cameras, the logic deviceand the one or more feedback output mechanisms may be enclosed in ahousing. The housing may be water-proofed for outdoor use. One or morewheels may be attached to the housing to allow it to be easily moved andpositioned. At least one input mechanism, such as touch screen display,may be mounted to the housing for configuring and operating the device.The touch screen display may be used to view one or more ofconfiguration information, operational information and sessioninformation. The feedback output mechanism may be a sound projectiondevice that can be enclosed within the housing.

The device may include an internal power supply for supplying power tothe device, such as a re-chargeable battery or a fuel cell. The powersupply may be enclosed in the housing. For outdoor models, photocellsmay be used for supplying power to the device and charging the battery.The device may also include a power interface for connecting the deviceto an external power source. The external power source may be used todirectly power the device or to charge a battery within the device.

In other embodiments, a video capture card for digitizing video framedata recorded by the one or more cameras. Using the video frame data,the logic device may be designed to generate a curve-fit of thetrajectory of the basketball. Further, the video frame data may includephysical information about the human, which may also be processed andanalyzed by the logic device. The logic device may be a general purposecomputer comprising: a processor, a data storage device, RAM, operatingsystem software, device interfaces, device drivers and trajectoryanalysis software. A mass storage device may be used for storing therecorded video frame data. Further, video editing software may be usedfor editing the recorded video frame data stored on the mass storagedevice.

The trajectory analysis device may include a number of communicationinterfaces for communicating with components of the system andperipheral devices connected to the system. As an example, the systemmay include a wireless network interface or a wire network interface forconnecting the logic device to one of a local area network, a wide areanetwork and the Internet. When connected one of these networks, thesystem may communicate with various devices also connected to thenetwork. A wireless interface may be used for providing communicationsbetween the one or more cameras and the logic device or for providingcommunications between the logic device and one or more peripheraldevices. Examples of peripheral devices that may communicate with thelogic device include hand-held computing devices, displays, wearablesound projection devices, kinetic feedback devices and printers.

In a particular embodiment, two or more cameras may be used forrecording video frame data. The two or more cameras may be mounted to abasketball hoop backboard Infrared light emitters may also be mounted tothe backboard. The emitters may be used to illuminate the basketball ininfrared light as it approaches the backboard. Thus, the two or morecameras may be capable of detecting infrared light reflected from thebasketball.

The components of the system may be enclosed in two or more housings andcommunication interfaces may be used for communications between thecomponents. For instance, a housing may enclose the cameras, lightemitters and a communication interface while the logic device andfeedback output mechanism may be located in a separate housing. Thus,the communication interface may be used for transmitting one of a) videoframe data, b) trajectory parameters, c) feedback information andcombinations thereof to the logic device. The housing with the two ormore cameras and infrared emitters may be mounted to a backboard. Thebackboard may be used outside. Therefore, the housing may bewater-proofed for outdoor use.

The feedback information supplied users of the device may be 1) one ofthe trajectory parameters, 2) a plurality of the trajectory parametersor 3) a feedback parameter generated from a combination of trajectoryparameters. The trajectory parameters may characterize different statesof the trajectory such as an initial state of the trajectory, a finalstate of the trajectory or states of the trajectory between the initialstate and the final state. The trajectory parameters used in thefeedback information may be selected based upon their benefit to thehuman in improving their shooting skills. A few examples of trajectoryparameters that may be generated for different states along thetrajectory include a release height, a release angle, a releasevelocity, an entry angle into a basketball hoop, an entry velocity intothe basketball hoop, an entry position of a center of the basketballrelative to a center of the basketball hoop, a transverse velocity ofthe basketball relative to a normal line drawn through the center of thebasketball hoop, a missed shot, a made shot, a rotation rate of thebasketball and axis of rotation of the basketball.

The feedback information may be provided to the human in at least one ofa visual format, an auditory format, a kinetic format and combinationsthereof. For instance, the feedback information may be a trajectoryparameter, such as release velocity, that is presented in a numericformat. The numeric format may be viewed by the human on a video displayor heard by the human from an audio device. In a particular embodiment,the feedback information may be used as input parameters for a videogame.

The device may be capable of generating trajectory parameters andproviding feedback information for each of a plurality of differenttrajectories in a trajectory session. The plurality of differenttrajectories may be shot from a plurality of different locations on abasketball court or approximately the same location, such as afree-throw line. The device may include or may be in communication witha memory storage device that is used for storing trajectory sessioninformation. The trajectory session information may comprise one or moreof 1) digitized video frame data, trajectory information and feedbackinformation generated for the plurality of trajectories, 2) a trajectorysession time, 3) a trajectory session date, 4) a trajectory sessionlocation and combinations thereof. The device may include a database forrelating the trajectory session information to human identificationinformation.

In a trajectory session, the plurality of basketball trajectories thatare detected and analyzed may be generated by a plurality of differentplayers. During the trajectory session, two or more basketballs may bein flight at a same time. The device may be capable of detecting,analyzing and providing feedback information for the trajectories of twoor more basketballs in flight at the same time. The two or more shotsthat are in flight at the same time may be generated by the same playeror may be generated by two or more different players.

The device may also include session analysis software. The sessionanalysis software may perform one or more of 1) providing a list or aplot of trajectory session information comprising one or more ofphysical information, trajectory parameters and feedback information forthe plurality of trajectories, 2) comparing the trajectory sessioninformation from the trajectory session with trajectory sessioninformation from one or more different trajectory sessions, 3)generating trajectory session parameters used to characterize a human'sperformance in the trajectory session, 4) predicting performanceimprovement as a function of the trajectory session parameters and 5)prescribing actions for improving performance.

Another aspect of the present invention provides a method of providingtrajectory detection and analysis for a trajectory of an object launchedalong its trajectory by a human. The method may be generallycharacterized as comprising: 1) receiving physical information about theobject along its trajectory from one or more sensors; 2) generatingtrajectory parameters from the physical information; 3) generatingfeedback information; and 4) providing the feedback information to thehuman. The feedback information may be provided to the human prior toend of the trajectory of the object or within a short time after the endof the trajectory of the object. The feedback information may beprovided in one of a visual format, an auditory format and a kineticformat.

The object may be launched by the human as part of game of skill, suchas basketball, where the objective of the game is to launch the objectalong a trajectory that terminates within a selected area. For instance,shooting a basketball into a basketball hoop. A playing area where thetrajectory is generated may be the playing area where the game of skillis normally played, such as a basketball court. The one or more sensorsmay be remote sensors that are located outside of the playing area orthe one or more sensors may be non-intrusive sensors located with theplaying area that do not affect the play of the game of skill in theplaying area.

In particular embodiment, the method may comprise one or more of thefollowing: a) recording video frame data wherein the one or more sensorsis a camera; determining a position of the object in a plurality of thevideo frames from the video frame data generating a curve-fit of thetrajectory of the object from the determined positions; and generatingone or more trajectory parameters from the curve-fit, b) prior togenerating the curve fit, digitizing the video frame data, c) prior todetermining the position of the object, editing out portions of thevideo frame data, d) receiving physical information from the one or moresensors from two or more objects in flight at the same time; generatingtrajectory parameters for the two or more objects; and providingseparate feedback information for each of the objects and e) generatinga list or plot of trajectory parameters for a plurality of trajectories.

In another embodiment, the method may also comprise generating one ormore aggregate trajectory parameters from the trajectory parameters froma plurality of different trajectories where the aggregate trajectoryparameters characterize the human's consistency. The aggregatetrajectory parameters may be a measure of statistical variability ofdifferent trajectory parameters. Thus, the method may also comprisepredicting performance improvement as a function of the one or moreaggregate trajectory parameters and generating a prescription comprisingone or more actions for improving performance.

Another aspect of the invention pertains to computer program productsincluding a machine-readable medium on which is stored programinstructions for implementing any of the methods described above. Any ofthe methods of this invention may be represented as program instructionsand/or data structures, databases, etc. that can be provided on suchcomputer readable media. Yet another embodiment of the present inventionis a system for delivering computer readable instructions, such astransmission, over a signal transmission medium, of signalsrepresentative of instructions for remotely administering any of themethods as described above.

These and other features of the present invention will be presented inmore detail in the following detailed description of the invention andthe associated figures.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagram of a trajectory capture and feedback scenarioemploying a trajectory detection and feedback system of the presentinvention.

FIG. 2. is a diagram of captured video frame data used to generate acurve-fit for a trajectory of an object.

FIG. 3 is a diagram of a second trajectory capture and feedback scenarioemploying a trajectory detection and analysis device of the presentinvention.

FIG. 4 is a block diagram of a trajectory detection and analysis systemof the present invention.

FIGS. 5A-5C are perspective drawings of a trajectory detection andanalysis system of the present invention.

FIG. 6 is an information flow diagram for of a trajectory detection andanalysis system of the present invention.

FIG. 7 is a shot scatter plot that may be provided by a trajectorydetection and analysis system.

FIG. 8 is an improvement map that may be provided by a trajectorydetection and analysis system.

FIGS. 9A and 9B are flow charts of methods for providing trajectorydetection and feedback using a trajectory detection and analysis system.

FIG. 10 is a perspective drawing of two embodiments of basketballtraining systems.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

The present invention provides methods and apparatus for trajectorydetection and analysis for trajectories of objects launched by a humanin games of skill. One objective of the methods and apparatus is togenerate feedback information that may be used by a participant in thegame of skill to improve their performance at the game. In a particularembodiment of the invention, a trajectory device is used to detect andanalyze a trajectory of a basketball shot by a human and providefeedback information about the trajectory to the shooter. However, thepresent invention is not limited to basketball and may be applied toother games of skill that involve object being launched along atrajectory, such as soccer, golf, football, baseball, softball, tennis,volleyball, racquet ball, bowling, water-polo, lacrosse, shot-put andjavelin.

In FIG. 1, a trajectory detection, analysis and feedback system using amachine vision system with a single camera to detect basketballtrajectories is described. In FIG. 2, details of determining trajectoryparameters from video frame data captured by the machine vision systemis described. In FIG. 3, another embodiment of a trajectory detection,analysis and feedback system using a plurality of cameras and infraredemitters to illuminate a tracked object is described. In FIG. 4, a blockdiagram with internal components of the trajectory detection, analysisand feedback system is discussed. In FIGS. 5A-5C, perspective diagramsof a trajectory device of the present invention are described. In FIG.6, details regarding an information flow and processing of data in thetrajectory system are provided. In FIGS. 7 and 8, two output formats forbasketball trajectory data generated from the trajectory system isdescribed. In FIGS. 9A-9B, methods of gathering trajectory data,providing session data and predictions of improvement to a user of thesystem are described.

FIG. 1 is a diagram of a trajectory capture and feedback scenarioemploying a trajectory detection and feedback system of the presentinvention. In the embodiment shown in the figure, a trajectorydetection, analysis and feedback system 100 uses a machine vision systemwith a single camera 118 to detect and to analyze a trajectory 102 of abasketball 109 shot towards the basketball hoop 103 by the shooter 112.The camera 118 may record visible light. A block diagram of the system100 is described with respect to FIG. 4.

The basketball hoop 103 may be mounted to a backboard 151 with a supportsystem to hold it up, such as a pole anchored into the ground, a supportanchored into a wall or supports suspended from a ceiling. Thebasketball hoop 103 may be of a standard height and the basketball maybe a standard men's size basketball. However, trajectories for abasketball of a different size, such as a women's ball, shot atbasketball hoop of varying heights may also be detected and analyzedwith the present invention.

The camera 118 in the machine vision system records physical informationwithin a detection volume 110. The physical information that is recordedis images of objects at a particular time in the detection volume 110.The images recorded at a particular time may be stored as a video frame106. The camera 118 may capture images of the basketball 109 as it movesin trajectory plane 104 as well as images of other secondary objects.The secondary objects may be closer to the camera than the basketball109 (i.e., between the camera 118 and the trajectory plane 104) or thesecondary objects may be farther away from the camera than thebasketball 109 (i.e., beyond the trajectory plane 104). The machinevision system may utilize software to distinguish between the movementof secondary objects that may be detected and the movement of thebasketball 109.

The trajectory detection system 100 may be set-up in a playing areawhere basketball is normally played, such as a basketball court withplaying surface 119 located in gymnasium or arena. The system 100 may bepositioned on the side of court and remotely detect the trajectories ofthe shots by shooter 112 using the machine vision system. Thus, theshooter 112 and defender 114 may engage in any of their normalactivities on the playing surface 119 without any interference from thedetection system 100. In the figure, the shooter 112 is guarded by adefender 114. However, the system 100 may also be used when the shooter112 is unguarded.

With a machine vision system that uses a single camera 118, thelocations where the trajectory 102 may be accurately analyzed may belimited. In one embodiment, with the set-up of the trajectory detectionsystem 100 on the side of playing surface 119, accurate analysis mayrequire that the shooter 112 shoot from within the active area 108. Inthis alignment, the trajectory plane 104 may be nearly normal to thebasketball backboard 151. Although, the system 100 may accurately detectand analyze trajectories where the angle between the trajectory plane104 and the normal to the backboard 151 is within a few degrees. Theactive area 108 may be different for different systems 100. Forinstance, in FIG. 3, a machine vision system employing three camera's isdescribed where the active area 108 is essentially any location on theplaying surface. Further, the present invention is not limited tomachine vision systems for detecting the trajectory of the basketballand other sensor systems may allow for different active areas.

The trajectory system 100 may be set-up in different locations aroundthe playing surface 119. By moving the system 100, the active area 108may be changed. For instance, the trajectory detection may be positionedbehind the backboard 151. For this set-up, the active area 108 may be arectangular area on the playing surface 119 that is parallel to thebackboard 151.

Although the active area 108 may be limited with a single camera 118 ina machine vision system, an advantage of the system is it simple toset-up and to operate. With some multiple camera machine vision systems,the active area may be larger than with a single camera system. However,the set-up and calibration of a multi-camera system may be more timeconsuming as compared to a single camera system because a knownalignment of the cameras relatively to one another and relative to thetracked object is needed to process the data.

The single camera system 100 is simple enough to be capable ofautonomous set-up and operation with minimal user input. The system mayautonomously calibrate itself using known distance markers, such as theheight of the basketball hoop or a distance to a free throw line or3-point arc, which may be captured in video frame data. In anotherembodiment, a user may be required to stand within the detection zone ofthe system, holding a basketball or other object, at a fixed distancefrom the camera and at a fixed height. After the system is calibrated, auser may use the system 100 to practice without the help of anadditional operator to run to the system 100. The system 100 may acceptvoice commands allowing the user to adjust the operation of the systemfrom a distance.

To analyze a trajectory 102 of the basketball 109, the camera 118 mayrecord a sequence of video frames in the detection volume 110 atdifferent times. The number of frames recorded by the camera over a givetime period, such as the duration of the ball's trajectory 102, may varyaccording to the refresh rate of camera 118. The captured video framesmay show a sequence of states of the basketball 109 at different timesalong its trajectory 102. For instance, the camera 118 may capture 1) aninitial state 105 of the trajectory shortly after the ball leaves theshooter's hand, 2) a number of states along the trajectory 102, such as120, 121, 122 and 123 at times t1, t2, t3 and t4 and 3) a terminationpoint 107 in the basketball hoop 103. Although not shown, the system mayalso be used to generate parameters for characterizing the trajectory ofmissed shots relating to the rebound flight path, such as but notlimited to a rebound height, rebound angle, rebound velocity.

The sequence of captured video frames may be converted to digital databy a video capture card for analysis by the CPU 116. The analysis ofvideo frame data may require the detection volume 110 to remain constantduring the trajectory 102. However, the detection volume 110 may beadjusted to account for different set-up conditions of a playing areawhere the system 100 is employed. For instance, the camera 118 may becapable of zooming in or out of a particular area and changing itsfocus. The analysis of the trajectory 102 using the captured video framedata is described with respect to FIG. 2.

The series of frames used to capture the trajectory may also capture theshooter 112 shooting the basketball 109 including all or a portion ofthe shooter's 112 body as well as the defender's body 114 during theshot. The physical information captured by the camera 118 regarding theshooter 112 and the defender 114 may also be analyzed by the system 100.For example, different motions of the shooter 112 may be analyzed by thesystem 100 determine if the shooter is using proper shooting mechanics.As another example, data, such as, a jump height, hang-time, a releasepoint floor position on the playing surface 109, a landing position onthe playing surface 109 may be determined using the video frame datacaptured by the camera 118 in the machine vision system.

After detecting and analyzing the trajectory 102, the system 100 maygenerate one or more trajectory parameters. The one or more trajectoryparameters may be output as feedback information to the shooter 112 andthe defender 114. Typically, the system 100 may provide the feedbackinformation while the shot is in the air or shortly after the shot hasreached the hoop 103. The feedback information may be provided withinless than a second or less than 10 seconds of the initiation of the shotdepending on the type of feedback information that is generated. Theimmediate feedback may increase the training benefits of using thesystem. The shooter 112 may use the feedback information to improvetheir skill at making shots. The defender 114 may use the feedbackinformation to improve their defense in preventing the shooter frommaking their shots. A brief description of the methods used to developthe feedback information is described as follows.

The shooter 112 may also use the feedback information for rehabilitativepurposes. For instance, after an injury and/or for psychologicallyreasons, a player's skill at shooting may decline from a previouslyobtained skill level. In rehabilitative setting, the present inventionmay be used by the player to regain their previous skill level and evenimprove upon their previous skill level. For instance, the feedbackinformation provided by the present invention may increase a shooter'sconfidence which may provide psychological benefits that lead to animprovement in performance.

To develop basketball feedback information, the basic nature of abasketball shot is considered with the objectives of 1) informing theplayer in regards to what are a set of optimal trajectory parametersthat they can adjust to increase their probability of making a shot and2) informing their player about how their shots compare to the optimal.This information is output to the player as feedback information. As anexample of this process, the basketball shot by the shooter 112 isdescribed. However, the system 100 may be applied to the trajectories ofother objects in different sports where optimal trajectory parametersmay be different than basketball. Thus, the description is presented forillustrated purposes only.

The basketball shot by the shooter 112 travels in an essentiallyparabolic arc in the trajectory plane 104. The arc is essentiallyparabolic and the ball 109 travels in-plane because after the ball isreleased the dominant force acting on the ball is gravity 109. Otherforces, such as ball spin, or if the ball is shot outside, wind, maycause the trajectory to deviate from a parabolic arc. But, when the ballis shot inside, these forces cause little deviation from the parabolictrajectory and a parabolic arc is a good approximation of the trajectory102.

For each shot by the shooter with an initial release height, there aremany different combinations of release velocity and release angles atthe initial state 105 that allow the player to make the shot, i.e., theball travels through the basket 103 and then many combinations ofrelease velocity and release angles where the player does not make theshot. When a player shoots the basketball 109, the player selects acombination of release velocity and release angle. Typically, theselection of the shot parameters is performed intuitively and the playerdoesn't consciously think of what release velocity and release anglethey are selecting. However, through training, the player may be able toimprove their intuitive shot selection.

Within the group of the different combinations of release velocity andrelease angle that may be selected by the shooter, there arecombinations of release velocity and release angle that provide theshooter with a greater or lesser margin of error for making the shot.For instance, for a basketball shot in the basket 103, an optimal entryangle into the hoop that provides the greatest margin of error is about43-45 degrees measured from a plane including the basketball hoop 103.These optimal trajectories are close to trajectories that allow for theball to reach to the basket 103 with a minimal amount of energy appliedby the shooter. For perturbations around this optimal entry angle, suchas when the defender 114 causes the shooter 112 to alter their shot,there are more combinations of release velocity and release angle thatallow the shot to be made as compared to other combinations of releasevelocity and release angle away from the optimal.

With the general understanding of basketball trajectories providedabove, methods may be developed for providing feedback information thatallows for the shooter 112 to train for an initial state 105 thatprovides the greatest margin of energy i.e., a near minimum energytrajectory. In one embodiment of the present invention, an entry angleand an entry velocity of the basketball 109 near the termination point107 are two trajectory parameters that may generated from the physicalinformation recorded by the machine vision system in system 100. Theentry angle and entry velocity are correlated to the release angle andthe release velocity of the shot 102. Thus, after the shooter 112,releases the shot, the camera 118 may record a series of video frameswith images of the ball 109 as it approaches the basket 103. With thisinformation, the entry angle and the entry velocity of the shot may begenerated. One or both of these trajectory parameters may be provided tothe player as feedback information.

The feedback information may be provided to the shooter 112 and thedefender 114 in one of a visual format, an audio format and a kineticformat. For instance, in one embodiment, on a visual display, the entryangle and/or entry velocity may be viewed in a numeric format by theplayers, 112 and 114. In another embodiment, when projected through anaudio device, numeric values for these parameters may be heard by theplayers, 112 and 114. The audio feedback device may be a speaker builtinto the system 100, a speaker connected to the system 100 or audiodevices worn by the players, 112 and 114 that receive information fromthe system 100. In yet another embodiment, a kinetic device, such as abracelet or headband worn by the players may be used to transmit thefeedback information in a kinetic format. For instance, the bracelet mayvibrate more or less depending on how close the shot is to the optimumor may get hotter or colder depending on how close the shot is theoptimum. Multiple feedback output mechanisms may also be employed. Forinstance, the feedback information may be viewed in a visual format bycoaches or other spectators on a display while a sound projection devicemay be used to transmit the feedback information in an audio format tothe players.

In general, the parameters may be presented qualitatively orquantitatively. An example of qualitative feedback may be a message suchas “too high” or “too low” in reference to the entry angle of a shot bythe player or “too fast” or “too slow” in reference to the entryvelocity. An example of qualitative feedback may be the actual entryangle or entry velocity of the shot in an appropriate unit ofmeasurement, such as a message of “45 degrees” for the entry angle.Again, the qualitative and/or quantitative information may be presentedin different formats, such as a visual format, an auditory format, akinetic format and combinations thereof.

With knowledge of what are optimal values of the trajectory parameterstransmitted in the feedback information, the shooter 112 may adjusttheir next shot to generate a more optimal trajectory. For instance, ifthe feedback information is an entry angle and their shot is too flat,then the shooter 112 may adjust their next shot to increase their entryangle. Conversely, with their knowledge of what are the optimal valuesof the trajectory parameters, the defender 114 may adjust theirdefensive techniques to force the shooter 112 to launch a shot along aless than optimal trajectory 102. Thus, the defender 114 can experimentwith different techniques to see which are most effective. In differenttraining methods, the system 100 may be used to measure a trajectoriesfor a shooter 112 training without a defender 114 or as is shown in thefigure training with the presence of a defender 114.

The feedback information may be provided to the player before prior tothe ball 109 reaching the basket or shortly after the ball reaches thebasket 103. The system 100 is designed to minimize any waiting timebetween shots. For each shooter and for different training exercises,there may be an optimal time between when the shooter shoots the ball109 and when the shooter 112 receives the feedback information. Thesystem 100 may be designed to allow a variable delay time between theshot and the feedback information to suit the preferences of eachshooter that uses the system 100 or to account for different trainingexercises that may be performed with the system. For instance, a rapidshooting drill may require a faster feedback time than a more relaxeddrill, such as a player shooting free throws.

The present invention is not limited to providing feedback informationfor near minimum energy basketball trajectories. For instance, undersome conditions, such as when a smaller player shoots over a largerplayer, it may be desirable for the shooter to shoot with a greater thanoptimal arc to prevent the larger player from blocking the shot. Thus,the shooter may use the feedback information provided by the system 100to train for different conditions that may call for different types ofshots, such as shooting over a larger player as compared to a wide-openshot. Further, the trajectory analysis systems of the present inventionmay be used to train in different types of basketball shots, such asbank shots, hook shots, lay-ups, jump shots, set-shots, free throws andrunning shots, that may requiring the mastery of different shootingskills and may have different optimal trajectory parameters. Thus, thedetection system 100 may be adjustable to allow for training indifferent types of shots. Further, for different sports, differenttrajectory skills may be optimal for improving performance, which may bedifferent than basketball. The different trajectory skills that may berequired for different sports may be accounted for in the presentinvention.

A measure of how good a player's shooting skills may be a consistency oftheir trajectory parameters averaged in some manner over many shots.Typically, it has been determined empirically that better shooters havea lower variability in their trajectory parameters for a given shot,such as a free throw. Thus, to rate a shooter's performance, it may bedesirable to generate trajectory parameters for a plurality oftrajectories shot by a player in a trajectory session and then calculatea standard deviation for each of the trajectory parameters.

The standard deviation (SD) is a measure of the scatter of a particularset of data. It is calculated as,SD=[3(y _(i) −y _(mean))²/(N−1)]^(1/2)where y_(mean) is an average value of trajectory parameter, N is thenumber of trajectories and y_(i) is a value of the trajectory parameterfor a particular trajectory. There are other types of statisticalparameters that may be used to characterize data variability and thepresent invention is not limited to the standard deviation formuladescribed above.

During a trajectory session where a plurality of trajectories areanalyzed by the system 100, the trajectory parameters generated for theplurality of trajectories may be stored to a mass storage devicecontained in the system 100 or in communication with the system 100.After the session, the standard deviation for all the trajectories inthe session may be generated. In other embodiments, to provide measuresof variability of different data sets representing different playingconditions, the system 100 may divide the trajectory data into differentsubsets, such as grouping according to types of shots, locations ofshots, shots where the shooter is guarded, shots where the shooter isunguarded, made shots, swished shots, missed shots, shots made earlierin the session versus shots made later in the session, and combinationsof these groupings.

The statistical variability calculated from the different data sets maybe used as a guide by the system for suggesting methods that willimprove the player's shooting skills. The system 100 may includesoftware for suggesting methods based upon the statistical analysis. Forinstance, the system 100 may determine that a player's shot variabilityis greater when they are guarded as opposed to unguarded, thus,exercises may be prescribed to the player that focus and shooting whileguarded. As another example, the player's shot variability may begreater later in a session as opposed to earlier in a session or greaterin a training session before practice as opposed to after practice,thus, the system may suggest the player work on their aerobicconditioning. In yet another example, the player's shot variability mayvary as a function of a distance from the basket and the system maysuggest the player concentrate on shots at the distances where thevariability is greatest. In FIGS. 7 and 8, plots of data from atrajectory session and predictions of improvement using statisticalanalysis are described.

In some embodiments, the trajectory session data and other informationgenerated by the system 100 may be viewed via a number of differentoutput mechanisms, such as a hard copy from a printer or a display. Forexample, a printer connected to the system 100 may be used to generateprint-outs of trajectory session data in different formats. As anotherexample, a display interface in communication with the system 100 may beused to view trajectory session data in different formats. Inparticular, the system 100 (see FIGS. 5A-5C) may include a touch screeninterface for viewing trajectory session data and providing inputparameters into the system. As another example, the system 100 (See FIG.4) may communicate with a portable viewing device capable of interfacingwith the system 100.

Information generated with system 100, such as trajectory data from aplurality of trajectories in a trajectory sessions, may be archived. Thearchival storage system may be a remote storage device in communicationwith the system 100 or may be a mass storage device provided with thesystem 100. The archival storage system may include raw data of physicalinformation recorded by the camera 118, such as video frame data, aswell as, trajectory parameters and other information generated fromanalysis of the raw data. The archival data may store trajectory sessiondata for a plurality of different trajectory sessions by one or moredifferent players.

By accessing the archival data, an improvement over time for aparticular parameter generated by the system 100, such as a shotvariability parameter, may be assessed. Further, the archival data maybe used for data mining and video editing purposes. For instance, in avideo editing application, the graphic of the player's averagetrajectory may be integrated with video data of the player shooting. Inanother example, video clips of two or more different players shootingmay be compared or video clips of a single player shooting duringdifferent trajectory sessions may be compared to show the player'simprovement. In data mining applications, the video data may be furtheranalyzed to characterize a player's shot mechanics. In anotherapplication, simulations may be generated to predict gains in teamperformance based-upon improvements in individual performance on theteam. This type of simulation may require archival trajectory sessiondata to be analyzed for a plurality of different players.

In some embodiments, the archival data may be accessible via a remoteconnection. For instance, a password-protected web-site may be used as aportal for accessing archival data generated from system 100. Theweb-site may allow clients, such as players, coaches, or scouts to gainaccess to the web-site from remote sites, such as home computerconnected to the Internet or a portable computer connected to theInternet. The web-site may include a plurality of analysis tools and agraphical interface for viewing graphical data from the applications indifferent formats. In another embodiment, the archival data may bedownloaded to a CD, DVD or other portable storage medium that the playercan take with them. Analysis software may also be downloaded with thearchival data so that the player can analyze the data on anothercomputer.

Information generated during a trajectory session may be stored in adatabase. The database may relate player identification information,such as a name, an address, a team, a session time, a session location,a session data to raw data recorded during the trajectory session andinformation generated during the trajectory session. The database may beused for player tracking purposes and targeting services to players thathave used the trajectory system.

FIG. 2 is a diagram of captured video frame data used to generate acurve-fit for a trajectory of an object. As described with respect toFIG. 1, in a machine vision system, images of objects may be recorded bya camera, digitized and converted into frame data. Four captured videoframes, 200, 201, 202, 203 are shown. The digitized frames capture animage of the ball 109 at times, t1, t2, t3 and t4 as it approaches thebasketball hoop 103.

Pattern recognition software may be used to determine the location ofthe ball 109 from other images that may be captured. In one embodiment,a reference frame is captured without a ball and the reference frame iscompared with the frames, such as 200, 201, 202, and 203 that containthe ball 109. In cases where the reference frame is relatively fixed,i.e., the only moving object is the ball 109. The ball 109 can beidentified via subtraction of the frames. The system may capable ofupdating the reference frame as needed to account for new objects thathave moved into the frame or have been removed from the frame.

When there is a lot of noise in the frame, such as people or otherobjects moving around in the frames, as well as the basketball, thenmore complex filtering techniques may be applied. In one embodiment, adata capture zone 214 may be identified in each frame. The data capturezone 214 may be used to eliminate any noise sources that may be mistakenfor the basketball and may be also be used to reduce the computationalresources required to analyze the frame data. For instance, theprocessing of the video frame data may be limited to the data capturezone or one or more other areas of interest within the captured frame.There are many pattern recognition and filtering techniques that havebeen developed for robotics, where machine vision is used, that are wellknown in the arts that may be applied to the present invention. Further,there are many techniques that have developed for signal or patternrecognition in noisy environments, such as those that have beendeveloped for recognizing valid aircraft radar signals and trackingmoving objects in commercial or military applications, that are wellknown in the arts that may be applied with the present invention.

Once the position of the object is determined from each frame. Acurve-fit for the trajectory may be developed in a computational space205 with a coordinate system 216. In the figure, for illustrativepurposes only, four points, 206, 207, 208 and 209 corresponding to timest1, t2, t3 and t4 are shown. As needed, additional frames may be used toproperly fit the data. For the basketball, the trajectory is assumed tobe parabolic and a parabolic curve-fit may be generated using a leastsquares curve-fit. The parabolic curve-fit accounts for gravitationalforces and neglects forces generated from drag and aerodynamic forcesresulting from spin. However, more complex trajectory curve-fits may bemodeled in the present invention that account for drag and spin. Thesecurve-fits may be more desirable for analyzing the trajectories ofobjects, such as a baseball, a football, a tennis ball, a soccer ball ora volleyball, where aerodynamic forces due to spin or drag are moreimportant.

In one embodiment, curve-fits 210 for x and y position may beparameterized as a function of time using a time at which each frame wasrecorded. In another embodiment, a curve-fit of height (y) as a functionof distance (x) in the coordinate system 216 may be generated. Using thecurve-fit, trajectory parameters, such as an entry angle 211 and theentry velocity 212 of the object as it enters the hoop, is near the hoopor at other states along the trajectory may be generated. For instance,the entry angle 211 may be generated from the tangent of the curve-fitat the termination point 213. The entry velocity 212 may be generatedfrom derivatives of the parameterized equations 210 at the timecorresponding to the termination point 213. If the release time isknown, then the release velocity and release angle may also bedetermined from the parameterized trajectory equations.

In one embodiment, trajectory parameters may be generated withoutcurve-fitting the entire trajectory. For instance, with enough positiondata near a particular location on the trajectory, such as thetermination point 213, then an entry angle may be calculated by simplyfitting a line through available data points near the terminationpoints. As another example, some trajectories may be non-parabolic but aparabolic curve-fit may be sufficient for estimating a trajectoryparameter, such a velocity, near a particular location.

In some embodiments, trajectory parameters may be generated for aportion of a trajectory captured in video frame data and analyzed in amanner described above. The trajectory parameters may be provided asfeedback information to a user of the system. For example, a trajectorysystem as described with respect to FIG. 1, may be setup on the side ofa baseball field and trajectory parameters, such as a release velocity,a release angle, a spin rate and a release height for a thrown baseball,may be generated with the present invention. The trajectory system mayonly detect and analyze the portion of the trajectory of the baseballnear the throwing release point. One or more of the trajectoryparameters or a combination of the trajectory parameters generated fromthe portion of the trajectory that is detected and analyzed may beprovided as feedback information to a baseball pitcher trying to improvetheir throwing skills. The pitcher that has thrown the ball can evaluatethe outcome of the pitch according to where it is caught by a catcher.

A similar approach could be applied to a football kicker kicking afootball or a soccer player kicking a soccer ball. In these instances, atrajectory detection system may be setup on the side of the field. Thesystem may capture video frame data that is used to generate trajectoryparameters of the football or soccer ball's trajectory as it leaves theplayer's foot and provide feedback information. The player kicking theball can then compare the feedback information to the success of thekick. For instance, how far the ball traveled, whether a field goal wasmade or whether a soccer goal was made.

In another embodiment, trajectory parameters may be generated for two ormore trajectory segments that are captured by video frame data andanalyzed in the manner described above. For example, as described withrespect to FIG. 1, a trajectory detection system may be setup on theside of a tennis court and the system may be used to measure trajectoryparameters for a tennis ball tossed by a player to initiate a serve. Thetoss of the serve is the first trajectory segment. The trajectorydetection system may generate trajectory parameters and feedbackinformation for the toss, such as a toss angle and a toss velocity and arelease height for the toss. Then, the player may strike the tennis ballwith a tennis racket to launch the tennis ball along the trajectory. Thetrajectory detection system may generate a second set of set oftrajectory parameters and feedback information for the second segment,such as, a height at which the ball is struck, an angle at which itleaves the racket, a velocity at which it leaves the racket and a spinon the ball after it leaves the racket.

In another example of providing feedback information to two trajectorysegments, the trajectory detection system may generate trajectoryparameters and feedback information at the release point of a thrownbaseball as described above. Then, the trajectory detection system maydetect a portion of the baseball trajectory as it crosses the plate andthen generate trajectory parameters for this portion of the trajectory,such as a height at which the ball crosses the plate and a velocity asit crosses the plate. These trajectory parameters for the secondtrajectory segment may be provided as a second set of feedbackinformation to the pitcher.

FIG. 3 is a diagram of a trajectory capture and feedback scenarioemploying a trajectory detection and analysis device of the presentinvention. In this embodiment, a machine vision system employing 3cameras 165 and 3 infrared emitters 164 is mounted above the backboard151 and the basketball hoop 103. The 3 cameras and 3 infrared emittersmay be enclosed within a housing 170. In another embodiment, the 3cameras and 3 emitters may be integrated into the backboard 151.Different multiple camera configurations may be used and the presentinvention is not limited to three infrared cameras mounted in a lineararrangement fairly close together. For instance, one embodiment of thepresent invention two cameras may be placed on opposite sides of theplaying surface 109, i.e. across the court from one another. Output fromboth cameras may be transmitted to a logic device for processing.

The backboard 151 is attached to a basketball pole, which is fixed tothe ground. In other embodiments, the machine vision system may bemounted to a backboard 151 that is attached to a portable supportsallowing the basketball goal to be moved around on a playing surface109. The support may also allow for the height of the goal to beadjusted. The machine vision system may be mounted to a backboard 151with a hoop 103 that is located outside. When the trajectory system isused outside, the housing 170 may be water-proofed to prevent waterdamage to the system.

The infrared emitters 164 may be used to illuminate objects that enterthe detection volume 110, such as ball 159 and ball 160. The infraredlight reflected from the objects may be detected and recorded by thecameras 165. When the cameras record both infrared and visible light,the cameras 165 may also include filters for minimizing visible lightcaptured in a video frame to enhance the infrared signature of objects.Using video frame data from the three cameras 165 with the knowndistances between each camera 165 and geometric relationships,trajectory parameters may be generated for trajectories of basketball'sshot from anywhere on the playing surface. For instance, when theplaying surface is a basketball court, then trajectories may be analyzedfrom basketball's shot anywhere on the court or even from beyond theboundaries of the court. This analysis capability differs from themachine vision system with a single camera that was described withrespect to FIG. 1. In the system of FIG. 1, the active area from which aplayer could shoot a shot and have it detected and accurately analyzedwas more limited.

An advantage of the infrared system is that the intensity at which anobject is illuminated decreases non-linearly according to the distanceof the object from the emitters 164. Thus, objects close to the emittersare clearly illuminated by objects but background objects that are faraway from emitters 164 are not illuminated. As was described withrespect to FIG. 2, with a camera that records in visible light,filtering methods may have to be applied to a series of video frames todistinguish the basketball from the movement from other objects that maybe moving in the series of video frames, such as spectators. With theinfrared system, since only objects close to the infrared emitters 164are clearly illuminated, i.e., objects within the detection volume 110,the need to apply complex filtering algorithms to account for themovement of other objects in the video frames may be eliminated. Forinstance, the infrared system may be able to detect and analyzetrajectories of basketballs in an arena or gymnasium where there aremany spectators in the field of view of the cameras 165.

Another advantage of the infrared system is that the basketballs 159 and160 may be marked with invisible infrared marking that are only visiblein infrared light. Thus, the players 152 and 153 shooting the balls 159and 160 marked with invisible infrared symbols would not be able todistinguish them from unmarked balls. The balls may be marked with asymbol or series of symbols to allow them to be distinguished by thesystem and associated with a particular player. For instance, ball 159may be marked with a plurality of triangles and ball 160 may be markedwith a plurality of squares in invisible ink that either glows underinfrared light or absorbs infrared light allowing the symbols to bedetected by the machine vision system. In addition, the balls 159 and160 may be marked with visible symbols to allow the players todistinguish between the balls.

The invisible infrared marking may also be used to aid in generatingtrajectory parameters. For instance, each of the seams of thebasketballs 159 and 160 may be marked with different invisible symbolsor patterns allowing the spin rate of the basketball and the orientationof the basketball to be measured. In general, the detection systems ofthe present invention may be used to measure one or more of thefollowing trajectory parameters for a basketball's trajectory: a releaseheight, a release angle, a release velocity, an entry angle into abasketball hoop, an entry velocity into the basketball hoop, an entryposition of a center of the basketball relative to a center of thebasketball hoop, a transverse velocity of the basketball relative to anormal line drawn through the center of the basketball hoop, a missedshot, a made shot, a rotation rate of the basketball and axis ofrotation of the basketball. Feedback information may include one or moreof the trajectory parameters or combinations of the trajectoryparameters, such as a ratio of entry velocity to entry angle.

The trajectory parameters that are generated may vary from system tosystem depending on the sensors used in each system. As described inFIGS. 1 and 3, with the present invention, machine vision systems may beemployed that use one or more cameras. The use of multiple cameras mayprovide measurement capabilities not possible with a single camera andhence capabilities to generate different trajectory parameters ascompared to a single camera system.

Further, the present invention is not limited to machine vision systemsfor detecting trajectories. Other types of sensor systems may be able togenerate different trajectory parameters than the machine visionsystems. For instance, there are many types of sensors systems that usedifferent types of emitters and detectors to detect the motion ofobjects. In these sensor systems, the emitter emits an energy signal andthe detector detects a reflected energy signal from the object. Thesesystems may be based on electromagnetic energy signals, such as radarsignal or a laser signal, or even acoustic energy signals.

As another example, non-intrusive sensors, such as accelerometers orvibration sensors, may be integrated into the object, such as 159 or160, a device worn by the players, 152 or 153, or other associatedequipment, such as the backboard 151 and the hoop 103. Information fromthese non-intrusive sensors may be utilized by the trajectory detectionsystem. In particular, a small (silicon chip based) sensor system with aRadio Frequency Identification (RFID) tag may be integrated into anobject, such as a basketball. The sensor chip may include sensors formeasuring accelerations and rotation rates for the object along itstrajectory. A microprocessor on the chip may be used to process thesensor data and an antenna may be used to broadcast signals to an RFIDtag reader. The sensor chip may be powered by an electromagnetic energyreceived from the RFID tag reader. As another example, the non-intrusivesensors, such as a sensor chip, may be integrated into items worn by theplayer, such as player's shoes or integrated into their clothes. Thesesensors may allow the trajectory system to detect forces that a player'sgenerates while launching an object, such as the directional forces, aplayer, such as 152 or 154, generates during a basketball jump shot.With this type of information, the player's release time may becorrelated to where the player is in their jump, i.e., is the ballreleased at the peak of their jump, on the way up or on the way down.Also, information, such as whether the player jumps straight up anddown, forward or backward or side-to-side may be determined. These typesof sensors may be denoted as non-intrusive because a player using a ballwith these types of sensors or wearing these types of sensors is notlikely to be aware of there presence unless directly told about theirpresence. However, in general, any type of sensor that does notinterfere with the player's normal play of the game may be considerednon-intrusive. For instance, a small sensor package worn by the playermay be considered non-intrusive if it does not interfere with their playeven though the player may be aware of the sensor package.

The present invention is not limited to one type of sensor system. Forexample, in some embodiments, combinations of sensor systems, such as amachine vision system, non-intrusive sensors integrated into thelaunched object, non-intrusive sensors worn by the player andemitter/detector systems may be used with the trajectory systems of thepresent invention. Further, the feedback information generated by thesystem may not be limited to trajectory parameters regarding theobject's flight. For instance, as described in the previous paragraph,non-intrusive sensors may be used to measure forces that a playergenerates while launching an object or a position of the player duringand after the launch of an object, such as shooting a basketball.Parameters regarding this information may be generated by the trajectorysystem and provided as feedback information to a system client, such as152, 153 and 154.

Returning to FIG. 3, two players, 152 and 153, are shown shooting twoballs, 159 and 160, that are in flight at the same time. The trajectorysystem may be capable of generating trajectory parameters and feedbackinformation for two or more object with trajectories in flight at thesame time, such as 161 and 162. When two objects collide before reachingthe basket 103 and are deflected, the trajectory system may be capableof determining whether a shot would have been made based upon trajectorydata measured before the objects collided.

Methods may be used by the system to distinguish between two or moreplayers that have shot a ball while using the trajectory system. Forinstance, as described above, the ball used by each player may be markedin some manner allowing the system to distinguish between which of thetwo or more players has shot a ball. In another example, non-intrusivesensors worn by the player or markings on clothes worn by the player mayallow the system to distinguish between players. The non-intrusivesensors may allow the system to determine when a particular player hasshot the ball. The markings on the clothes, such as a different jerseyworn by each player using the system, may allow the system todistinguish between players.

When the system can distinguish between two or more players using thesystem simultaneously, trajectory session data may be generated andarchived for each player, which may be advantageous. Also, when thesystem can distinguish between players, the system may be able toprovide personal feedback information to each player via feedbackinterfaces worn by the players. For instance, player 152 that has shotthe ball 159 is wearing a feedback interface device 164, which providesfeedback information in a kinetic format and player 153, which has shotthe ball 160 is wearing a feedback interface device 164, which providesfeedback information in an auditory format. In this embodiment, thesystem detects and analyzes the trajectories of balls, 159 and 160,generates trajectory parameters, determines which player has shot whichball and provides feedback information to each player via theirrespective feedback interface devices, 163 and 164. The feedbackinformation is sent to each player's feedback interface device via awireless communication interface used by the trajectory feedback system.

In another embodiment of the present invention, to provide feedbackinformation two or more players using the system simultaneously, thetrajectory system may use shot location to distinguish between players.The trajectory curve-fits may be used to determine a location where ashot was initiated. Thus, the two or more players may be assigned aparticular area on the playing surface 109 in which to shoot. Then, thesystem may store data from each shot area that has been assigned to aparticular player to a storage area for that player. The players may beassigned a particular communication frequency for their feedbackinterface device. Since the player is identified from the location fromwhich the shot originated, the proper communication frequency forsending feedback information to each player may be selected.

In yet another embodiment, one or more players may shoot from one sideof the basket 103 and one or more players may shoot from the other sideof the basket 103. A speaker, such as 167 mounted to backboard 151 or aspeaker located on the playing surface 109 on the same side of thebackboard 151 as the speaker 167, may provide audio feedback informationfor shots originating from the side of the basket 103 where the speaker166 is located. A speaker, such as 167 mounted on the other side of thebackboard 151, may provide feedback information for shots originatingfrom the side of the basket 103 where this speaker is located. Inanother embodiment, the players, 152 and 153, may take turns shootingand the speakers 166 and 167 may project the same feedback informationto the player that has shot the ball. The speakers 166 and 167 areoptional and all backboard mounted systems may not include backboardmounted speakers, such as 166 and 167.

The trajectory system may generate feedback information that is receivedby system clients other than the shooters. For instance, coaches andspectators may desire feedback information for player's using thesystem. For instance, a system client 154, such as a coach, a scout or aspectator, may receive feedback information via a visual display tablet155 via wireless communication 156 from the trajectory system. Whenmultiple players are using the system, the system client 154, may beable to view feedback information for two or more players simultaneouslyor may be able to select feedback information from an individual playerfor viewing. For each player, the display tablet may allow the systemclient to view the feedback information in different formats, to viewtrajectory session data for the current trajectory session and to viewarchived trajectory session data from previous trajectory sessions todetermine a player's training progress and may be able to view recordsof a training program that a particular player is following. In general,the system may be able to support simultaneous communications with aplurality of different peripheral devices that may be used by systemclients including but not limited to hand-held computing devices,displays, wearable sound projection devices, kinetic feedback devices,printers and remote servers.

The functions of the trajectory systems of the present invention may beprovided in a device with a single housing or more be divided among anumber of different devices with separate housings. In addition, thetrajectory system may be constructed in a modular fashion to allowdifferent modules to be added to provide increased functionality. Forexample, one trajectory system may include the infrared emitters 164,cameras 165, logic devices for processing the video data and generatingfeedback information and a wireless communication interface forcommunicating with the feedback interface devices and other peripheraldevices, such as the remote server 157. The emitters, cameras, logicdevice and wireless communication interface may be enclosed in as singlehousing 170. If desired, the trajectory system may be configured tocommunicate feedback information to additional feedback outputmechanisms that may be connected to the system, such as speakers 166 and167. The devices in the housing 170 may be configured with a number ofdifferent settings. For the backboard mounted system, control inputs maybe provided through a feedback interface device with a touch screen orother input controls, such as display tablet 156.

The system in housing 170 may not include storage and session analysiscapabilities or only limited storage and session capabilities. Forinstance, it may only store data from a current session and may notarchive data in a database containing records for a plurality ofdifferent players. However, these features may vary from system tosystem. In one embodiment, the trajectory detection system component 150may comprise a mass storage device, a logic device, a display and aprinter for storing, analyzing and outputting trajectory dataaccumulated over a trajectory session and a database for storing recordsfrom a plurality of different players. This device may be added as amodular component to the system in housing 170. The plurality oftrajectories may be analyzed by the system enclosed in housing 170 andthen transmitted via wireless communication 158 for storage and analysisto the trajectory detection system component 150. A remote server 157may provide this functionality. Many trajectory system and componentconfiguration are possible with the present invention and the examplesof system modularity and division of functionality between systemcomponents has been provided for illustrative purposes only.

FIG. 4 is a block diagram of a trajectory detection and analysis system100 of the present invention. As was described with respect to FIG. 3,the components of the system 100 may be enclosed within a single housingor may be divided between a plurality of different housings enclosingdifferent components of the system. Further, the system 100 may includedifferent components that are not shown, such as the peripheral devicesand remote servers described with respect to FIG. 3.

Physical information 216 is input into the system 100 via sensors 212.In one embodiment, a machine vision system may be used where the machinevision system comprises one or more cameras 201 (e.g., a CCD camera) anda video capture card 203 for digitizing captured frame data. The videocapture card 203 may capture color pixel data. The camera 201 may employa 3.5-8 mm zoom lens and may allow for different lens attachments. Inanother embodiment, the system may employ a plurality of camerasarranged on a mechanism that allows different type cameras to be rotatedor moved into place where only one camera is used at a time to recordframe data. The different cameras may allow the detection volume of thesystem to be adjusted.

The digitized frame data from a machine vision system and other sensordata may be processed by a computer 202. The computer 202 may be amodified PC using a 1.6 GHz processor 204 w/RAM and a CD-RW drive 205for inputting and outputting data and software. The computer 202 mayalso include a mass storage device, such as hard drive 207 and variousnetwork/device communication interfaces, such as wireless and wirednetwork interfaces, for connecting to a local area network (LAN),wide-area network (WAN) or the Internet. The device communicationinterfaces may allow the computer to communicate with a plurality ofperipheral devices and other remote system components.

The computer 202 may include operating system software 206 forcontrolling system resources, such as feedback interfaces 213 and thesystem input/output mechanisms 215. The computer 202 may be used toexecute analysis software 208 for analyzing trajectories using thesensor data from sensors 212 and for generating feedback information217. The analysis software 208 may include software for providingvarious services, such as 1) providing a list or a plot of trajectorysession information comprising one or more of physical information,trajectory parameters and feedback information for the plurality oftrajectories, 2) comparing the trajectory session information from thetrajectory session with trajectory session information from one or moredifferent trajectory sessions, 3) generating trajectory sessionparameters used to characterize a human's performance in the trajectorysession, 4) predicting performance improvement as a function of thetrajectory session parameters, 5) prescribing actions for improvingperformance and 6) performing video editing tasks. The computer 202 mayalso be used to execute database software for relating physicalinformation 216 and other information generated by the computer 202 toplayer identification information (e.g., name, age, address, team, etc.)and session identification information (e.g., time, data, location,number of trajectories analyzed, types of shots, etc.).

Power to the computer 202 and other devices may be provided from thepower supply 209. In one embodiment, the power supply 209 may be are-chargeable battery or a fuel cell. The power supply 209 may includeone or more power interfaces for receiving power from an externalsource, such as an AC outlet, and conditioning the power for use by thevarious system components. In one embodiment, for in-door/outdoormodels, the system 100 may include photocells that are used to providedirect power and charge an internal battery.

Feedback information 217, used by clients of the system 100 to improvetheir trajectory skills, may be output through one or more feedbackinterface devices 213, such as a sound projection device 211. Ingeneral, the system may be capable of outputting feedback information217 to a plurality of different devices simultaneously in a plurality ofdifferent formats, such as visual formats, auditory formats and kineticformats.

The system 100 may support a plurality of different input/outputmechanisms 215 that are used to input/display operational information218 for the system 100. The operational information 218 may includecalibration and configuration setting inputs for the system and systemcomponents. In one embodiment, a touch screen display 210 may be used toinput and display operational information 218 using a plurality menus.Menus may be available for configuring and setting up the system 100,for allowing a player to sign into the system and to select preferredsetting for the system 100 and for viewing session information 219 invarious formats that have been generated by the system. The printer 214may be used to output hard copies of the session information 219 for aplayer or other client of the system 100. The present invention is notlimited to a touch screen display as an interface for operationalinformation. Other input mechanisms, such as but not limited, a keyboard, a mouse, a touch pad, a joystick and a microphone w/voicerecognition software may be used to input operation information 218 intothe system.

FIGS. 5A-5C are perspective drawings of a trajectory detection andanalysis system 100 for one embodiment of the present invention. Acamera 201 used in a machine vision system, a touch screen display 210,a computer 202 and a sound projection device 211 are integrated into ahousing 300 with a support chassis 301. The system 100 may also includean amplifier for the speaker 211 (not shown). Other devices describedwith respect to FIG. 4 that are not shown, such as a power supply, mayalso be integrated into the housing.

Wheels 304 are attached to the chassis 301 to allow the system 100 to beeasily moved and positioned for use, such as on the side of a basketballcourt or another location where the system is employed. In general, thechassis of devices of the present invention may be designed with aweight and a form factor, which may facilitate transport, storage andunobtrusive set-up, calibration and operation of the device. Forinstance, the device includes a handle 303 attached to panels 300comprising the housing that may be used to move the device and which mayaid in set-up and storage of the device.

The speaker 211 takes up a large portion of the internal volume of thesystem. In one embodiment, a travel system may be used that incorporatesa portable computer system such as laptop that is connected to a machinevision system with the camera 201. To use the travel system, it may beplaced on top of a support platform, such as a tripod, a table, or achair. The support platform may be positioned on the side of abasketball court. The travel system may provide feedback information viaa wireless communication interface to audio device, such as an “earbud,”worn by the player. In another embodiment, the travel system maygenerate output signals that may be routed through a portable audiosystem (e.g., a boom box) for amplification via speakers on the audiosystem to provide feedback information.

FIG. 6 is an information flow diagram for a trajectory detection andanalysis system of the present invention. A sensor system 502, which maycomprise emitters 506 and detectors 506, receives physical information507. The physical information 507 may be energy signals reflected from atracked object 508. In the case where sensors are mounted to the trackedobject 508, then the physical information 507 may be sent as signalsfrom the sensors to a detector 504. Typically, the physical information508 is transmitted through a medium such as air.

The sensor system 502 may convert the physical information 507 to sensordata signals 509. For instance, a charge coupling device generateselectronic signals in response to photons striking a sensor array. Thesensor data signals 509 may be sent through a wired or wirelessconnection to a sensor interface 510, which provides signalconditioning. The signal conditioning may be needed to allow the sensordata 509 to be processed. For instance, in the machine vision systemdescribed with respect to FIGS. 1-4, prior to analysis, the video framedata is digitized by a video capture card.

In 513, the conditioned signals 511 may be processed according to systemcontrol software and according to trajectory analysis software 513 usingset-up and control inputs 512 that have been input into the system. Thesystem control software 513 may analyze portions of the data 511 todetermine whether the sensor system 502 is operating properly.Based-upon the analysis of the data 511, the system control software mayprovide calibration instructions and other operational instructions tothe sensor system which may be transmitted to the sensors via the sensorinterface 510.

The trajectory analysis software 513 may be used to process theconditioned signals 511 and generate trajectory parameters. Thetrajectory parameters may be used to generate feedback information. Thefeedback information may be one or more trajectory parameters or acombination of trajectory parameters, such as a ratio of trajectoryparameters or a product of trajectory parameters that may be useful to asystem client in improving their trajectory skills.

Depending such factors as the application (trajectory of a specific typeof object), the set-up and components of the system, the environment inwhich the system is used and what portion of the trajectory of an objectthe device is used to measure, the present invention may providefeedback to the player nearly immediately, within a second or within 10seconds as measured from some time state along the trajectory that hasbeen analyzed by the system. For instance, when information on thebeginning of the trajectory is directly generated by the system, thenthe time to provide feedback may be measured from the time when thetrajectory is initiated and then first detected by the system. Wheninformation on the end of the trajectory is directly measured, then thetime to provide feedback may be measure from the time to when thetrajectory has neared completion and has been detected by the system.

The feedback information may be sent as feedback information parameters516 to one or more device interfaces 517. The device interfaces 517 maycommunicate with a plurality of feedback devices. The device interfaces517, which may include device drivers, may transmit device data/commands518 to a feedback device interface 519 located on each feedback device.The device data/commands 518 may be used to control the operation of thefeedback devices. The output from the feedback device may also bemodified using set-up/control inputs 520 that may vary for each device.

The feedback devices may output the feedback information parameters 516received as device data 518 in one of an audio, visual or kinetic format521 depending on the capabilities of the feedback device. For example,the device interface 517 may send device data/commands 518 to a displaythat allows a numeric value of a feedback information parameter 516 tobe viewed on the display by one of the system clients 522, such asplayers, coaches and spectators. As another example, a device interface517 may send device data/commands 518 to an audio output device thatallows feedback information parameters 516 to be output in an audioformat to one or more of the system clients 522.

The feedback parameters 516 generated from the trajectory analysissoftware 513 and other raw data generated from the sensor system 502 maybe sent to session storage 515. The session storage 515 may accumulatetrajectory data from a plurality of trajectories generated during atrajectory session for one or more players. All of a portion of thetrajectory data 514 may be sent to archival storage 525 when the sessionhas been completed. For example, only a portion of the raw data, such asvideo frame data, may be sent to archival storage. Further, the data maybe filtered for bad data prior to being sent to archival storage 525.The archival storage 525 may include a database used to relatetrajectory data from one or more trajectory sessions to the conditionsof the trajectory session, such as time place and location, and playeridentification information.

The archival data 524 and session data 514 may be used to provide one ormore services 523 including but not limited to 1) a session record oftrajectory parameters (see FIG. 7), 2) session diagnostics, 3)prescription for improvement (see FIG. 8), 4) a history comparison oftrajectory data from different sessions, 5) individual/group comparisonsof trajectory session data, 6) video analysis and editing tools, 7)simulations (e.g., predicting a team's improvement based upon improvingone or more members of the teams shooting skills and 8) entertainment.As an example of entertainment, a player's trajectory average trajectoryparameters and variability may be used in trajectory simulations for avideo basketball game or another game where the parameters have beenmeasured. Two players that have used the system 100 may both enter theirparameters and compete against one another in the video game. The playermay also use the game to see how they match up against professional orcollegiate athletes who have had their trajectory parameters defined.

Output from the data services 523 may be converted to a portable record527, such as print-out from a printer, or may be formatted for viewingon a graphical interface 528. The graphical interface may also include astorage capacity allowing data to be viewed at a later time. The outputfrom the data services 523, such as a portable record 527 or informationviewed on the graphical interface 528, may be used by the system clients522. The data services 523 may also be provided via a data mininginterface 526. The data mining interface 526 may include analysis toolsand a graphical interface. When the archival storage is remotelyaccessible, it may be used to access archived data 524 via a remoteconnection, such as from the Internet.

Information passed between the different components in the system asdescribed with respect to FIG. 6 may be transmitted using a number ofdifferent wired and wireless communication protocols. For instance, forwire communication, USB compatible, Firewire compatible and IEEE 1394compatible hardware communication interfaces and communication protocolsmay be used. For wireless communication, hardware and softwarecompatible with standards such as Bluetooth, IEEE 802.11a, IEEE 802.11b,IEEE 802.11x (e.g. other IEEE 802.11 standards such as IEEE 802.11c,IEEE 802.11d, IEEE 802.11e, etc.), IrDA, WiFi and HomeRF.

FIG. 7 is a shot scatter plot 400 that may be provided by a trajectorydetection and analysis system. The shot scatter plot 400 shows entryvelocity 402 (feet per second) versus entry angle 404 (degrees) for aplurality of different shots that were generated during a trajectorysession. As was described with respect to FIG. 1, the entry velocity 402and entry angle 404 are trajectory parameters that may be generated froma trajectory detection system of the present invention and provided asfeedback information to the player using the system during thetrajectory session.

The basketball shots are divided into three categories, swish 406,rim-in 408 and miss 410. Swish shots 406 pass through hoop withouttouching it. Rim-in shots 408 hit the rim and then pass through thehoop. Miss shots 410 do not pass through the hoop. The plot 400 may beused to provide the player a visual record of how well they did in thesession and how much entry angle and entry velocity vary from shot toshot. If the shots were all taken from the same location, such as thefree throw line, then a margin error of for the shot may be gaugedapproximately from the figure. The margin of error can be gauged becausethe plots shows which combinations of entry velocity and entry anglelead to made shots and which combinations lead to missed shots.

FIG. 8 is an improvement map 420 that may be provided by a trajectorydetection and analysis system of the present invention. The map 420 is afunction of the release height of the shot, which 9 feet and 6 inches,and the average entry angle, which is 41 degrees. The improvement map420 provides contours of a percentage of shots made as a function ofvelocity variability 414 and an angle variability 412. The velocityvariability 414 and angle variability 412 may be calculated as astatistical deviation generated from a plurality of shots taken during atrajectory session. As the angle variability 412 and the velocityvariability 414 approach zero for a particular shot, the shootingpercentage approaches 100%.

For an initial trajectory session, a baseline 416 of velocityvariability and entry angle variability is about 0.4 and 1.4respectively. This variability pair provides for a shooting percentagein the range 40-50 percent. The improvement map 420 predicts that if theplayer reduces their velocity variability to about 0.2 and their anglevariability to about 1, then their expected improvement 418 will be anincrease in shooting percentage to about 70-80 percent from 40-50percent.

Using this improvement map, the player may be prescribed a series oftraining exercises that will improve their angle variability 412 andvelocity variability 414. If the player participates in a plurality oftrajectory sessions, then angle variability and velocity variability foreach session may also be plotted on the improvement map. Thus, theplayer can see how they are approaching their goal as a function oftime. Further, the player can use the trajectory system to verify thattheir shooting percentage is actually increasing as their velocityvariability and angle variability is decreased. Also, they can comparetheir actual shooting percentage with the predictions generated in theimprovement map 420.

FIGS. 9A and 9B are flow charts of methods for providing trajectorydetection and feedback using a trajectory detection and analysis system.In FIG. 9A, a method of detecting, analyzing and providing feedbackinformation for a trajectory is described. In 600, the system receivessensor data, such as video frame data from a camera, from the sensorsystem regarding the motion of an object along a trajectory. In someembodiments, the system may be capable on analyzing the trajectories oftwo or more objects simultaneously. In 606, using the sensor data 606,the system generates one or more trajectory parameters from sensor datathat describe an aspect of the object's trajectory. In 608, using thetrajectory parameters, feedback information is generated. The feedbackinformation may be one or more of the trajectory parameters or acombination of trajectory parameters. In 610, the feedback informationis provided to one or more system clients, such as a player or coach.The feedback information may be provided to the client via a feedbackoutput mechanism, such as a sound projection device or a visual displaydevice.

In another embodiment, the method may also comprise generating one ormore aggregate trajectory parameters, such as a statistical deviation,from the trajectory parameters from a plurality of differenttrajectories where the aggregate trajectory parameters characterize thehuman's consistency. The aggregate trajectory parameters may be ameasure of statistical variability of different trajectory parameters.Thus, the method may also comprise predicting performance improvement asa function of the one or more aggregate trajectory parameters andgenerating a prescription comprising one or more actions for improvingperformance.

In FIG. 9B, a method of detecting, analyzing and providing feedbackinformation for a trajectory is described using a machine vision system.In 601, video frame data of an object along to trajectory is recordedusing one or more cameras in a machine vision system. Prior to recordingthe object along its trajectory, a reference frame without the objectmay be generated and the machine vision system may be calibrated byrecording images of the object at prescribed positions relative to theone or more cameras. In 602, the frame data captured from the one ormore cameras may be digitized using a video capture card. In 603, theposition of the object in each of plurality of captured video frames maybe determined. Filtering and pattern recognition methods may be appliedto pick out the object in the video frames. The position of the objectin each frame varies as the object travels along its trajectory. In someembodiments, two or more objects that are in flight at the same time maybe captured in the video frame data and the system may be capable ofdetermining trajectories for each of the objects.

In 604, a trajectory curve-fit may be generated for the object using theposition data from the video frames. Using time data from each frame,the curve-fits of the object's trajectory may be generated as a functionof time. Also, curve-fits of the object's height as a function ofdistance may also be generated. In 606, using the curve-fits and/or theposition data from the frames, trajectory parameters may be generatedfor the trajectory. In 608, using the trajectory parameters, feedbackinformation is generated. In 610, the feedback information, via anoutput mechanism, is provided to one or more system clients, such as aplayer or coach.

FIG. 10 is a perspective drawing of two embodiments of basketballtraining systems, 700 and 702. The basketball training systems of thepresent invention may use any of the embodiments of the trajectorydetection, analysis and feedback systems and devices previouslydescribed herein. Thus, in FIG. 10, the particular embodiments oftrajectory detection, analysis and feedback systems and their associateddevices are provided for illustrative purposes only.

The basketball training systems, 700 and 702, may each comprise aplaying area 109, a basketball hoop 103, a backboard 151 and trajectorydetection, analysis and feedback system. In the basketball trainingsystem of 700, the trajectory detection, analysis and feedback systemcomprises a camera 728, an audio feedback device 718, a visual feedbackdevice 716 and a logic device, such as computer 704, for performingtrajectory analysis and generating feedback information. In basketballtraining system 702, the trajectory detection, analysis and feedbacksystem comprises a fixed camera 724 mounted to backboard 151, a movabletrajectory device 722 and a visual feedback device 716. In particularembodiments, the camera 724 may be designed to allow it to be mounted invarious locations, such as clipped to the backboard or mounted to thewall adjacent to the backboard. The movable trajectory device 722 mayinclude calibration software and settings that allow different mountlocations for camera 724 to be utilized.

In 702, the movable trajectory device 722 may comprise a camera that isused in a machine vision system, a touch screen display, a computer anda sound projection device integrated into a housing, as is describedwith respect to FIGS. 5A-5C. The sound projection device may be used toprovide feedback information to the player. The movable trajectorydevice 722 may receive input, such as visual frame data, from the camera724. In one embodiment, the trajectory device 722 may use the inputreceived from the camera 724 to determine whether a shot was made ormissed.

In a particular embodiment, the trajectory device 722 may allow a userto listen to music of their choice while using the training system. Thetrajectory device 722 may include a memory for storing music andprogramming logic for allowing a user to select music of their choiceduring a training session. A player's musical preferences and otherpreferred optional settings on the system may be stored by the systemand associated with the player so that a player doesn't have to inputtheir selection each time.

In one embodiment, the device may include one or more input ports fordownloading music onto the system from a portable device, an interfacethat allows a user to use a portable music device, e.g., an MP-3 player,such as an IPOD™ by Apple™ (Cupertino, Calif.) with the system, anoptical disk drive for playing optical disks storing music or acommunication interface allowing music to be downloaded from a remoteserver. During a training session, a player's musical selection may beoutput via a sound projection device coupled to the training system 702.When feedback information is provided in an audio format, the feedbackinformation and any musical output may be integrated to allow both to bediscerned. For instance, when audio feedback information is provided, itmay be over-laid on top of the musical output the volume of thebackground music or feedback information may be each adjusted up or downso that the feedback is heard. In another example, the audio feedbackinformation may be output from a separate speaker than the music or fromonly one channel of a speaker system (e.g., right or left channel) whena stereo system is included.

In another particular embodiment, the camera 724 may be used to provideadditional information about a body position and body mechanics of theplayer utilizing the training system 710. The camera 724 may capture aposition or an alignment of a player's torso, head, arms, etc., duringand/or after a shot. This information may be combined with informationobtained from camera used in device 722. The trajectory device 722 mayanalyze the player's body position captured from the camera 724 and/orthe camera in device 722 to provide additional feedback informationand/or recommendations that allow a player to improve their shootingskills. The camera 724 and/or device 722 may be positioned at differentlocations to capture different visual data regarding a player's bodyposition while still providing trajectory analysis and feedback. In someembodiments, such as when the camera 724 is not present, only the camerain device 722 may be used to gather visual data for an analysis of aplayer's body mechanics during shooting. In other embodiments,additional cameras, besides the camera 724 and the camera in device 722may be used.

In analyzing a player's body mechanics, the trajectory device 722 may beused to determine a trajectory of one or more parts of the player's bodyduring and after a shot. For example, the trajectory device 722 maydetermine an arc of a player's foot/or knee to determine whether theplayer move upwards in a vertically aligned direction or in a directionoff of vertical. In another example, the trajectory device may measurean arc of a player's elbow or hand to determine whether the player'sarms is imparting sideways momentum to the ball and to determine whetherthe player's is properly following through on the shot.

In one embodiment, during a training session comprising a number ofshots, the body positioning information determined for each shot may becorrelated with information characterizing the shot, such as trajectoryparameters and the feedback information derived from the trajectoryparameters. Thus, after or during a training session, the trajectorydevice 722 may analyze the shots, group them in some manner and thendetermine whether there are characteristics of each group related to aplayer's body mechanics that distinguish one group from the other group.

For example, during a training session, the trajectory device 702 maygroup a first number of shots a player has taken as good shots (e.g.,shots with an arc within a proscribed range and made) and group a secondnumber of shots as bad shots (e.g., shots with an arc out of aproscribed range that were made or missed). Then, the trajectory device722 may compare the player's body mechanics for shots in each group tosee if there are any characteristics that distinguish the shots in thegood group from the shots in the bad group. For instance, in the badgroup, the player may have had a poor follow through that resulted in abad shot.

Information related to their shooting mechanics may be provided in someformat to the player. For example, a player may be shown visual outputfor different shots in a side-by-side manner, in series (one shot, thenanother shot) or one on top of the other (e.g., overlaid) by makingusing graphical techniques to make one of the shots semi-transparent.When the shots have been grouped in some manner, then one shot from afirst group and one shot from a second group may be shown forcomparison. In addition, shot comparison may be shown for two or moreshots made by a single player and also for two or more shots made bydifferent players. For instance, a player may be able to compare theirshot with the shot of one of their favorite professional players. Theshots compared and output by the system may be for shots made during acurrent or previous training session using the training system.

The visual display device 716 or a display device on 722 may be used todisplay a comparison of the different shots. From the comparison,differences in the player's biomechanics between the shots may beevident. When the trajectory device has performed an analysis anddetermined a biomechanical difference between the shots, such as a poorfollow through for shots in one group versus a good follow through forshots in another group, the differences may be illustrated on thedisplay with additional graphics added to the previously captured visualdata. For instance, the visual recording of the player's hand or arm maybe highlighted with additional graphics, such as an added arc thatfollows the motion of the player's hand, to illustrate what is good ornot good about the player's follow through.

The categorization of shots into groups, such as “good” shots and “bad”shots, may be also used to illustrate a player's training progress.During a training session or over multiple training sessions, utilizingthe feedback information generated by the trajectory device 722, aplayer's biomechanics may naturally improve as they learn what a “good”shot feels like using the feedback information. Thus, the player maytake more “bad” shots earlier in a session or in previous sessions usingthe device and then later improve to make more “good” shots. From acurrent and/or previous training sessions, the trajectory device 722 maycategorize various shots and then show a comparison of shots fromdifferent groups, such as one or more “good” shots and one or more a“bad” shots. The player, coach or a trainer may be able to identify animprovement in their mechanics by visually comparing the selected “good”and “bad” shots.

The trajectory system 702 may be operable to output the visualcomparison to a visual display device coupled to the system or aprinter. In addition, the trajectory system may be operable to storevisual data to a DVD or some other optical storage device. Further, thetrajectory system 702 may be operable to store it to a local/remotememory for archival purposes, store it to a portable storage device,such as a thumb drive (e.g., portable hard drive or flash drive), toe-mail to a specified e-mail address or the like.

The criteria used to group good and bad shots is variable and may dependon one or more different trajectory parameters and their combinations aswell as an analysis of a player's shooting mechanics and is not limitedto the examples described above, which are provided for illustrativepurposes. Thus, in some instances, a made shot with a good arc may becategorized a “bad” shot because of a player's poor shooting mechanics.Conversely, in other instances, a missed shot may be categorized as a“good” shot, because the shot had a good arc and the player used goodshooting mechanics.

As described above, in some instances, the trajectory device 722 mayperform an analysis of the player's biomechanics (shooting mechanics) ineach shot an attempt to identify differences that led to the improvementand when the trajectory device 722 has identified differences, these maybe illustrated graphically in some manner as part of the visual output.Further, the trajectory device 722 may use an analysis of a player'sbiomechanics to prescribe exercises or drills that could improve aplayer's shot. For example, the trajectory device 722 determines aplayer's biomechanics are off in some manner, such as a player is notfollowing through properly on a shot with their hand or some other partof their body is moving in a less than optimal manner, then thetrajectory device may recommend exercises to improve the player'sdetermined deficiency.

A prescribed exercise to improve an identified proficiency of a playermay or may not involve shooting. In the case of shooting, the trajectorydevice 722 may be programmed with various exercises. The programmedexercises may comprise types of shots jump, set or bank, distance ofshots (e.g., 5 ft, 10 ft, free throw line, under the rim, from the side,etc.), number of shots, etc. For example, a prescribed shooting exercisemight comprise 5 jump shots from the free throw line, followed by 5 setshots from the 3-point line. In regards to systems 700 and 702, detailsof shooting programs are described in further detail below.

Returning to FIG. 10, the trajectory device 722, may be coupled via awired or wireless communication links to the backboard mounted camera724 and visual feedback device 716. Further, the trajectory device 702may include a communication interface or a mechanism for connecting to acommunication interface that allows the trajectory device 702 tocommunicate with other trajectory detection, analysis and feedbacksystems, such as the system associated with training system 700.

Basketball training systems 700 and 702 may include bounding structures,such as 710, around the circumference of the playing areas 109. Althoughnot shown, the bounding structures 710 may surround the playing areas109 on four sides to form a rectangular box-like shape. The structures710 may be secured in a fixed location and relatively rigid (e.g., likethe walls of a racquet ball court) or removable and flexible made ofvarious suitable materials, including materials that absorb impact. Inparticular embodiments, removable netting, curtains, partition wallswith wheels, may surround a portion of or the entire circumference ofthe playing areas 109. Thus, for example, using movable curtains, astandard size basketball court may be partitioned into many smallerareas to allow the use of multiple basketball training systems and thenlater converted back to a standard size basketball court for game play.

An impact absorbent material may include padding to absorb an impact ofa player or when the training system is adaptable for other sports, suchas golf or baseball. The material may be designed to absorb impact ofthese objects, golf balls or baseballs, hitting the wall. Further, thematerial may designed to prevent ricochets of these objects from hittingthe wall and then striking a player.

The dimensions, width 712 and length 714, of the basketball trainingarea 109 may be significantly smaller than the length and width of astandard basketball court which is 84-94 feet long and 50 feet wide. Forexample, in FIG. 10, the length 714, may be proximately 26 feet whichallows a pro 3-point shot of 23.75 feet to be taken and the width may beabout 14 feet which is wider than the 12 ft lane of a basketball of astandard basketball court. Smaller or larger playing areas 109 withtheir associated dimensions may also be used and the present inventionis not limited to the previous example. The lines of a standardbasketball court, such as the free throw line which is 15 feet from thebackboard 151 and 3 feet from the front of the rim may be also beincorporate as part of the playing areas 109.

In one embodiment, the width 712 doesn't have to be centered evenly oneach side the basket 103. For example, on one side of the basket, thewidth 712 may be just larger than the lane, while on the other side ofthe basket 103, the width 712 may extend to the dimensions of a standardbasketball. These asymmetric dimensions may allow shots to be taken fromone side of the basket 103 that are of any length available on astandard basketball court. On the opposite side of the basket 103 someshots of a length available on a standard basketball court may not beavailable.

In the case where the width 712 of the playing area is significantlynarrower than the width of a standard basketball court, in oneembodiment of the present invention, the basketball training systems mayinclude a rotation device 720. The rotation device 720 may be coupled tothe backboard and its associated support in a manner that allows thebackboard 151 and basket to be rotated between 0 and 90 degrees in onedirection or between 0 and 90 degrees in two directions. The trainingsystems, 700 and 702, may include input devices, such as a touch screendisplay, that allows an operator to select a shot program that includesor doesn't include a rotation of the backboard 151 during a trainingsession.

The rotation device 720 may also be coupled to the backboard and itsassociated support in a manner that allows the backboard 151 and basketto be rotated between 0 and 90 degrees while keeping the position of thehoop constant, thus having the center of rotation being the center ofthe hoop. When a player moves around a hoop, the hoop remains in a fixedposition. Thus, a better simulation of shooting on full-sized basketballcourt may be provided by rotating the backboard 151 in a manner thatallows the hoop 103 to maintain a constant position in space as thebackboard rotates. In one embodiment, a rotation through the center ofthe hoop 103 may be generated by placing the rotation mechanism 720above the backboard with its axis of rotation through a center of thehoop 103 and then providing a connector bar of some shape from the axisof rotation of the rotation mechanism 720 to the back board 151. In thisembodiment, when the rotation mechanism 720 is engaged, the position ofthe hoop 103 will appear to remain constant because the hoop 103 and thebackboard 151 rotate around the center of the hoop 103.

The rotation device may be coupled to a logic device utilized by thetraining systems 700 and 702, such that the backboard 151 and goal 103are rotated automatically during a training session on the trainingsystems. When the backboard and basket are rotate, the training systemsare operable to perform trajectory analysis and provide feedbackinformation while accounting for the changing orientation of thebackboard 151 and basket 103 as a function of time. At start-up and/orduring operation, the training systems may perform calibration functionswith the backboard and basket 103 at different positions to check if thesystem is properly set-up.

Besides rotation, the backboard may be capable of vertical motion. Forinstance, for younger players, the mechanism 720 may also allow thebackboard 151 and basket 103 to be lowered. Further, young players mayuse a smaller ball. Thus, the training systems, 700 and 702, may beoperable to provide trajectory analysis and feedback for basketballhoops at various heights, at changing angles and for balls of differentsizes.

In particular embodiments, the basketball training systems 700 and 702may include ball return mechanisms. The ball return mechanism may be apassive device that alters the momentum but doesn't add to the momentumthat the basketball possesses when it reaches the device. For instance,the curved ramp 706 alters the momentum of a basketball, such as 160,such that it is directed away from the basket 103. As shown in thefigure, the curved ramp 706 won't typically alter the trajectory ofbasketball if it is a missed shop. Other passive devices, such asnetting, may be employed to direct a ball away from the basket 103 formissed shots.

The ball return mechanism may also be an active device that addsmomentum to balls and directs them toward a player. For instance, intraining system 702, an active ball return device 740 is used thatreceives both made and missed shots and then shoots out a basketball.The ball return mechanism 740 may be operable to hold a plurality ofbasketballs.

The ball return mechanism 740 is coupled to netting 708 that directsboth missed and made shots to the ball return mechanism. One advantageof using a playing area 109 that is smaller than a standard basketballcourt with bounding structures 710 around the perimeter of the playingarea 109 is that the bounding structures 710 constrain the ballsallowing the netting 708 to be placed below the backboard 151. Withoutthe bounding structures to constrain the balls, such as on a full-sizecourt, the netting 710 has to be placed higher than the hoop to capturea majority of missed shots. When netting is higher than hoop, it blocksthe player's view and it doesn't simulate actual playing conditionswhich is undesirable to players. Another advantage of a smaller playingarea is that it allows more training systems to be utilized in a smallerarea, which may be more economically and advantageous for facilitiesthat are space constrained. For example, 4 training systems might beplaced in the width of a standard basketball court and its sidelines.

In one embodiment, the ball return mechanism may include controls thatallow the ball to be returned to different spots on the playing area109. For instance, the device 740 may be coupled to a motor that allowsthe device to be rotated and/or elevated to direct balls to differentlocations. Similar, to the rotation device 720, in some embodiments, thelocation where the ball is passed may be automatically controlled by thetraining system 702 as part of a shooting program or the location may bemanually adjusted. The active ball return feature may allow the playerto perform “catch” and “shoot” exercises during their training sessionwhere the player receives a “pass” from the return device 740 at one ormore different locations on the playing area and then shoots afterreceiving the pass.

The training systems, 700 and 702, as part of training session, may beoperable to direct a player to particular locations on the playing areas109 as part of a shot program. As an example, as part of a shootingprogram, the trajectory systems, 700 and 702, may direct players tolocations 730, 734, 736 and 738. The player may take one or more shotsat each of these locations as part of a shooting program.

A number of different methods may be used to direct a player todifferent locations. In one embodiment, locations on the playing areas109 may be marked in some manner, for instance, each of the circles 730,734, 736 and 738 may be painted a different color or painted with anumber and the training system may provide an audio command, such as“blue,” “free throw line,” “3-point line,” or “one,” to direct a playerto a particular location. In another embodiment, a visual display devicesuch as 716 may include a map of the playing area. When the player isdirected to change location, a sound or command, such as “changelocation” may be output via a sound projection device and then alocation on the map of the playing area may be indicated in some manner.

In yet another embodiment, lights may be integrated into the floor ofthe playing areas 109. For example, lights may be integrated atlocations 730, 734, 736 and 738. These lights may light up under controlof the training system to indicate different shooting locations. In aparticular embodiment, the training systems may include a movablespotlight or a projection device, such as 728, that projects visiblelight or an image to certain locations on the playing area 109, such as730, 734, 736 and 738. The training systems may automatically controlthe movable spotlight or projection device(s) as part of a shootingprogram.

The training systems, 700 and 702, may be operable to determine whethera player is shooting from a particular location. For example, when amachine vision system is used for the trajectory analysis and feedback,the machine vision location may be also used to determine from which thelocation the player has shot on the playing surface. As another example,the playing area may include sensors for detecting a player's location,such as an integrated pressure sensor or a light sensor that isactivated when it is partially covered by a player's foot. In addition,the player may wear a device, such as a wireless device that allowstheir location on the player area 109 to be determined.

The system may also be operable to compare the player's actual location(determined by the system) with a location where the player is supposedto be located as part of a shooting program. The location detectionsystem may look for the player's feet to be within and/or touching acircle of some specified radius. When the player's actual location isdifferent from the location from where they are supposed to be locatedas part of a shooting program the system may output instructions orinformation, such as “not at specified location.” If the system isscoring the player's performance in a shooting program, then shots fromincorrect locations may affect the player's score. The locator functionmay or may not be active as part of a shooting program.

As part of a shooting program, a player may be able to compete againstone or more players in a tournament. The training systems 700 and 702,which may be systems at the same or different locations, i.e., at thesame facility, such as a gym or at different facilities, such asdifferent gyms in different cities, may be operable to send data toother training systems and receive data from other training systems. Thetraining systems 700 and 702 may be operable to communicate with oneanother and other training systems or another device providing remotecommunications via a local area network or a wide area network, such asthe Internet. Thus, in particular embodiments, each system may include anetwork communication interface that allows for one of a wired orwireless connection to one or more of the local area network or the widearea network.

In one embodiment, two or more players may start a shooting program atthe same time, which is scored in some manner. For example, a player maybe awarded points for shots made as well as an amount of time taken tocomplete the drill. In FIG. 10, player “A” using system 700 is competingagainst player “B” using system 702 and each system is sending data toone another. In the FIG. 10, a time left and a score for theircompetition is shown on the visual displays 716.

To generate a competition, two or more players don't necessarily have touse a training system at the same time. For example, a first player mayparticipate in a shooting program where there results are recorded, suchscore as a function of time. Later, a second player may compete againstthe first player using their recorded data and the same shooting programthat the first player used. As the second player goes through the sameshooting program as the first player and generates a score, the firstplayer's scores at corresponding times may also be shown. Using thisapproach, a player may also compete against themselves by repeating ashooting program and competing against results of the shooting programthat they have previously generated.

The competition results may be shown on the visual display 716. In oneembodiment, the system may store an archive of top “scores” or player'sof interest, such as “pro” players that a player can compete against.Further, the systems may be operable to allow players to compete overtime or against one another in a league type format.

In other embodiment, the backboard and basketball may be replaced withimages projected onto the wall of the bounding structures 710 and intoair, i.e., space between the bounding structures. The system may includeblank walls and floors that are suitable for image projection. Forprojecting into the space between the bounding structures, a number oftechnologies exist. For instance, IO2 technology (S. San Francisco,Calif.) provides a “helio” display that allows an image to be displayedon a “sheet” of compressed air. Thus, various compressors for providingsheets of air at different location may be integrated into the system. Asheet of compressed air at the height of basket 103 in combination witha projector may be used to generate a projection of a hoop that a playermay use as a target. Technology for generating 3-D spots of plasma inair has also been demonstrated by The National Institute of AdvancedIndustrial Science and Technology, in Japan.

Using the “helio” display or plasma generation technology or some othersuitable projection technology, a hoop may be generated in 3-D space andlines on a backboard projected on to one wall. The player may shoot theball towards this projected hoop where the system is operable todetermine whether the ball has passed through the hoop or not. A missedshot may be result in a projection of a rebound from the hoop projectedinto to space while the “physical” ball bounces to the ground. Further,an audience may be simulated on the walls and other players to provide amore authentic experience.

In another embodiment, a player may where goggles or head gear thatproject images or lines into space. These images or lines integratedinto a player's field of view. Thus, a virtual basketball and backboardmay be projected into the player's field of vision and the player mayshoot the ball towards the image projected using the goggles. Thegoggles may be used in conjunction with head and/or eye tracking toprovide a player with the proper views. For instance, wearing thegoggles, the player may turn away from the virtual basketball hoop andthe image of the hoop will no longer be displayed to the player. Thistype of application may also be referred to as a “mixed” reality. MixedReality is the merging of real world and virtual worlds to produce a newenvironment where physical and digital objects can co-exist andinteract.

Using a projection and/or goggle system, the basketball training systemmay be easily adapted to other sports. For instance, a virtual hoop orhoops could be used as targets for football training system. A similarenvironment could be used for pitching a baseball, fielding a baseballand throwing to first base, hitting a baseball from a pitching machine,throwing a pass, hitting a tennis serve, hitting a volleyball serve orspike, etc. The first base or running receiver/defenders or tennisnet/lines or volleyball net/lines would be 3-D projections. Further,physical games may be played in this generic environment againstcompetitors that are virtual (computer generated or real people over thenetwork.) The trajectory analysis and feedback system may provide thetrajectory of the object, thus providing feedback for training orcalculating gaming expertise for scoring. The system may allow data tobe stored and retrieved or displayed to an audience.

Although the foregoing invention has been described in some detail forpurposes of clarity of understanding, it will be apparent that certainchanges and modifications may be practiced within the scope of theappended claims.

What is claimed is:
 1. A system comprising: a basketball including asensor system, disposed within the basketball, for measuring motions ofthe basketball wherein the sensor system includes a first wirelessinterface for sending sensor data related to the motions of thebasketball to an electronic device; the electronic device including aprocessor and a memory and a second wireless interface for receiving thesensor data, said processor configured to 1) receive sensor data for aplurality of repeated motions of the basketball, 2) based upon thereceived sensor data, generate one or more parameters that characterizethe plurality of repeated motions, 3) based upon the one or moreparameters, generate feedback information that is used to characterize askill of a person at generating the repeated motions and 4) output thefeedback information wherein, when the repeated motions are a pluralityof basketball shots, an angle of the trajectory of each of the pluralityof basketball shots relative to a plane of a basketball hoop when thebasketball is proximate to the basketball hoop is determined from thereceived sensor data associated with each shot and the feedbackinformation is based upon the determined angles.
 2. The system of claim1, wherein the repeated motions are shots towards a basketball hoop. 3.The system of claim 1, wherein the sensor system includes anaccelerometer.
 4. The system of claim 1, wherein the sensor systemincluding one or more sensors for measuring a rotation rate of thebasketball.
 5. The system of claim 1, wherein the sensor system includesa power interface for receiving power wirelessly.
 6. The system of claim1, wherein the sensor system includes a microprocessor configured toprocess the sensor data.
 7. The system of claim 1, wherein theelectronic device is configured to generate and output the feedbackinformation after a completion of the training exercise.
 8. The systemof claim 1, wherein the electronic device is configured to receive thesensor data for a portion of the plurality repeated motions while themotions are being performed, generate the one or more parameters basedupon only the portion and output the feedback information while therepeated motions are being performed.
 9. The system of claim 8, whereinafter the sensor data for the portion of the plurality of repeatedmotions is received, the electronic device is configured to receiveadditional sensor data and generate the one or more parameters basedupon the portion and the additional sensor data.
 10. The system of claim1, wherein the electronic device is configured to receive simultaneouslyfirst sensor data from a first basketball and second sensor data from asecond basketball, generate first one or more parameters based upon thefirst sensor data and second one or more parameters based upon thesensor data, generate first feedback information based upon the firstone or more parameters and the second feedback information based uponthe second one or more parameters.
 11. The system of claim 1, whereinduring each of the repeated motions, the basketball is in contact with ahand of the person during a first part of the motion and not in contactwith the hand of the person during a second part of the motion andwherein the one or more parameters characterize the second part of themotion.
 12. The system of claim 1, wherein the one or more parametersinclude an average speed of the basketball during the repeated motions.13. The system of claim 1, wherein the one or more parameters include anaverage rotation rate of the basketball during the repeated motions. 14.The system of claim 1, wherein the one or more parameters include anaverage angle associated with a direction in which the basketballtravels during the repeated motions.
 15. The system of claim 1, whereinthe electronic device is further configured to generate the one or moreparameters and the feedback information based upon on only one of therepeated motions.
 16. The system of claim 1, wherein the electronicdevice is further configured to determine a training exercise forimproving their skill at performing the repeated motions and outputinformation related to the training exercise as part of the feedbackinformation.
 17. The system of claim 1, wherein the electronic device isfurther configured to generate a score based upon the one or moreparameters wherein the feedback information includes the score.
 18. Thesystem of claim 1, wherein the electronic device is configured togenerate a trajectory of the basketball during one of the repeatedmotions and output the trajectory.
 19. The system of claim 1, furthercomprising: an image capture device for capturing one or more images ofthe person while the person is performing the training exercise.
 20. Thesystem of claim 1, wherein the feedback information is related to howconsistent is the person at generating the repeated motions.
 21. Thesystem of claim 1, further comprising: a display for outputting thefeedback information.
 22. The system of claim 21, wherein the display isa touch screen display.
 23. The system of claim 1, wherein the repeatedmotions are part of a training exercise.
 24. The system of claim 1,wherein the feedback information includes information for helping theperson to improve their skill at generating the repeated motions. 25.The system of claim 1, wherein the electronic device is a portablecomputer system.
 26. A system comprising: a basketball including asensor system, disposed within the basketball, for measuring motions ofthe basketball wherein the sensor system includes a first wirelessinterface for sending sensor data related to the motions of thebasketball to an electronic device; the electronic device including aprocessor and a memory and a second wireless interface for receiving thesensor data, said processor configured to 1) receive sensor data for aplurality of repeated motions of the basketball, 2) based upon thereceived sensor data, generate one or more parameters that characterizethe plurality of repeated motions, 3) based upon the one or moreparameters, generate feedback information that is used to characterize askill of a person at generating the repeated motions and 4) output thefeedback information wherein, when the repeated motions are a pluralityof basketball shots, a velocity of the basketball at one or moretrajectory locations near the basketball hoop, including trajectorylocations after the basketball enters the basketball hoop, is determinedfrom the received sensor data associated with each basketball shot andthe feedback information is based upon the determined velocities.